1. Field of the Invention
The present invention relates to a sheet outputting apparatus of an image forming apparatus that performs a post process of a sheet on which an image is formed by a copier or the like.
2. Description of the Related Art
Conventionally, a sheet on which an image is formed and outputted from an image forming apparatus such as a copier having a post-process apparatus that is called a sorter is accepted by a bin which is selected from a plurality of bins. Recently, a copier, particularly, a digital copier is commercially available as a composite apparatus which is provided with additional functions such as a printer mode and a facsimile mode, in addition to a copy mode that is originally provided to a copier. To comply with this, as a post-process apparatus which is to be disposed in a digital image forming apparatus, an apparatus having functions such as a mail box in addition to a function as a sorter is commercially produced.
A prior art technique of a post-process function is disclosed in, for example, Japanese Unexamined Patent Publication JP-A 5-306064(1993). In a copier of the prior art technique, information of the number of copy sheets allowed to be accepted by each bin of a sorter is previously stored. If it is judged that, on the basis of the stored information of the allowable sheet number, and information of the number of originals which is designated in a copy job, the allowable sheet number is smaller than the number of original sheets, copy sheets are distributed to be accepted by two or more bins through an arbitrary number of steps, and an excess number of copy sheets exceeding the allowable sheet number is distributed to a bin adjacent to a bin which has no space anymore to accept a copy sheet.
Recently various digital composite copiers having functions of a facsimile, a network printer and the like are produced. Furthermore, also many kinds of post-process apparatuses such as a mail box which automatically distributes record sheets on which an image is formed are produced. In a function such as a sorter or a mail box, however, bins to which sheets are to be discharged must be previously designated. When various functions are used during a process of discharging sheets, therefore, there arises a problem in that, unless a bin to which sheets are to be discharged is efficiently selected, discharging of sheets for a subsequent job is not conveniently carried out. In the prior art disclosed in Japanese Unexamined Patent Publication JP-A 5-306064 (1993), when the number of sheets to be discharged exceeds the allowable sheet number of a bin, sheets are discharged also to other bins. In the prior art technique, however, considerations to an efficient use of bins for discharge disposed in a sheet outputting apparatus, and to easy discharge of sheets in a subsequent job are not taken.